Initial Commit ...

Mongo/XMongoReadPreferenceResolver.cs

@@ -0,0 +1,23 @@
+using MongoDB.Driver;
+
+namespace xDataService.Mongo {
+    public static class XMongoReadPreferenceResolver {
+        public static ReadPreference GetEffectiveReadPreference (
+            IClientSessionHandle session,
+            ReadPreference explicitReadPreference,
+            ReadPreference defaultReadPreference) {
+            if (explicitReadPreference != null) {
+                return explicitReadPreference;
+            }
+
+            if (session.IsInTransaction) {
+                var transactionReadPreference = session.WrappedCoreSession.CurrentTransaction.TransactionOptions.ReadPreference;
+                if (transactionReadPreference != null) {
+                    return transactionReadPreference;
+                }
+            }
+
+            return defaultReadPreference ?? ReadPreference.Primary;
+        }
+    }
+}